Trim attachment for power boats

ABSTRACT

A trim plane or other control surface for a water vessel is operated by a pressure space such as a flexible bag between the trim plane and the hull or an extension thereof. The bag is inflated by water under pressure through a conduit leading from an opening in a surface subjected to the flow of water around the boat. The pressure may be changed by changing the surface geometry in the proximity of the opening. This may be accomplished by an auxiliary flap behind the opening which flap is operated by the pilot through remote control.

United States Patent Inventor Ali Martin Magnus lngelman-Sundberg Stockholm, Sweden App]. No. 786,195 Filed Dec. 23, 1968 Patented Sept. 14. 1971 Assignee Hmeiman Bil-Am AB Stockholm, Sweden Priority Dec. 29, 1967 Sweden 17,958/67 TRIM ATTACHMENT FOR POWER BOATS 9 Chills, 12 Drawing Figs.

US. Cl 1l4/66.5 Int. Cl. 1363b 1/22 Field of 114/665 P; 244/78 Reierences Cited UNITED STATES PATENTS 1.761590 6/1930 Klemperer 244/78 2,492,252 12/1949 Wing 244/78 2.753,835 7/1956 244/78 X 3,046,928 7/1962 l 14/66.5 3,026,839 3/1962 Fridge 114/665 3,428,012 2/1969 lngelman-Sundberg 1 14/665 Primary Examiner-Andrew H. Farrell A!!orney-Young & Thompson FIG.1

IN V EN TOR.

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TRIM ATTACHMENT FOR POWER BOATS The present invention is concerned with water-going vessels such as power boats and relates to a device intended to influence the attitude or course of the vessel in the water by means of a control surface such as a trim surface or a rudder surface which coacts with the bypassing water whilst generating control forces exerted on the vessel.

Such arrangements are already known in the form of trim flaps for boats. The trim flaps known heretofore, however, have the disadvantage that they are either fixed in position and cannot therefore be adjusted in accordance with different operating conditions of the boat, or require a complicated operating system to provide for the desired adjustment of the flap.

The object of the present invention is to provide an easily operatable device of the aforedescribed type. This object is achieved with a device of the type described in the introduction which is mainly characterized in that to provide for variation of the magnitude of the control force exerted to the control surfaces, the angle of the control surfaces in relation to the flow direction of the water is adjustable by means defining a pressure space with variable volume and situated between the control surface and the portion of the vessel influenced by the control force, said space communicating with an opening in a surface coming in contact with the bypassing water so that said space can be subjected to the pressure created locally at this surface by the bypassing water.

The pressure space may have any suitable shape and can exert an appreciable force on the control surface. The operating force is obtained from pressure built up by the passing water.

In a preferred embodiment the device is provided with means for changing the surface geometry in the immediate vicinity of the opening, whereby the pressure occurring in the opening, and thus in the interior of said space, can be varied. The control surface is thus operated with a servo action by varying the flow conditions in the proximity of the opening.

The invention is also concerned with another device for changing the surface geometry of the vessel, this device being mainly characterized in that there is positioned behind the opening in the flow direction of the water on the surface in which the opening is disposed a regulator flap, the dimensions of which are small in relation to the control surface and which can be swung from its support surface to produce a desired pressure at the opening. The regulator flap and its operating means comprise a servosystem for actuating the control surface proper. The regulating flap can be operated by very small forces in comparison with the relatively large forces which may be required to actuate the control surface.

In a preferred embodiment of the invention the device forms a compact unit which can be attached to the vessel without difficulty and without requiring complicated conduit systems, and consists of but a few components. This embodiment of the device according to the invention is characterized in that the opening is disposed in the actual control surface and that the regulator flap is attached to said surface behind the opening.

The regulator flap can be operated in any suitable manner, e.g. by means of a mechanical transmission from the pilot seat. A convenient arrangement for operating the regulator flap is mainly characterized in that attached between the regulator flap and the support surface is a regulator flap actuator bag, the interior of which communicates with pressure setting means adapted to set the pressure of said bag and thus elevation of the regulator flap.

Instead of or in addition to changing the surface geometry in the immediate vicinity of the opening it is possible to obtain difierent pressures in the opening by placing the opening in a sensing body which can be adjusted so that the opening can be caused to adopt different positions in relation to the flow direction of the water for the purpose of varying the pressure prevailing at the opening, and thus in said pressure space. In

another preferred embodiment of the invention, which is mainly characterized in that the sensing body comprises a cylindrical body rotatable about its axis and in the cylindrical surface of which the opening is disposed, the opening communicating with the space via a passage in the cylinder body and a conduit, continuous regulating possibilities are obtained between the full value of the dynamic pressure of the water and a certain subpressure.

The invention also enables the attitude of a vessel to be regulated automatically with a stationary pressure opening by actuation of trim surfaces. Such an arrangement is mainly characterized in that the opening is disposed in a surface which is situated at the rear portion of the vessel in such a position that the opening senses such changes in the waterflow which occur as a result of changes in the attitude of the vessel. In the case of a large angle of attack on the vessel, and thus also on the surface provided with the opening, pressure occurs in the opening, and the trim flap is held extended. When the vessel adopts a planing attitude with small angle of attack, the pressure in the opening decreases or disappears so that the pressure space is emptied and the trim flap is retracted. A preferred position for the surface presenting the aforementioned opening is on the stern of the side of the vessel.

The invention, however, is not restricted to trim surfaces for power boatsor to devices or arrangements for regulating the attitude of the vessel in the water, but may also be adapted for steering the vessel. This is achieved by mounting a control surface on either side of the rudder of the vessel and providing said vessel with control means for selective actuation of the control surface to provide for changes in the course of the vessel. The vessel can be controlled by means of said device in two ways. Either the rudder can be fixed in position, the control surfaces functioning as rudder surfaces, or the control surfaces situated at the rear edge of the rudder operate as servomechanisms which cause the rudder to swing, thereby steering the vessel.

In one preferred embodiment, the pressure space is formed by a flexible bag. Sealing problems between movable parts are thus eliminated and installation facilitated. This embodiment also permit simple fitting to curved surfaces. However, the arrangement according to the invention does not necessarily have to have a completely tight pressure space in order to operate, but a limited leakage can be tolerated.

The invention will now be described in more detail with reference to the accompanying drawings, in which:

FIG. 1 shows in plan view a boat provided with two alternative devices for operating trim surfaces situated at the stern of said vessel,

FIG. 2 is a side view of the boat illustrated in FIG. 1,

FIG. 3 is a perspective view seen obliquely from the rear,

FIG. 4 is a longitudinal section through the stern of a boat provided with a device for operating trim surfaces of FIGS. 1 and 2, the main and regulator flaps being shown in different planes,

FIGS. 5 and 6 are longitudinal sections similar to that of FIG. 4 and show two alternative arrangements for operating trim surfaces,

FIGS. 7 and 8 seen from below and the side, respectively, show a further embodiment for automatically operating trim surfaces, a portion of the device in FIG. 8 being shown in longitudinal section,

FIG. 9 shows a horizontal section through the rear portion of a rudder seen along the line 9-9 in FIG. 10 which, similar to FIG. 11 shows in side view the stern portion of a boat, and

FIG. 12 shows an alternative embodiment for operating a trim flap.

FIG. 1 shows a boat in plan view, provided with two different arrangements for operating trim flaps situated at the stern of the vessel. The arrangement on the port side of the vessel is also shown in FIG. 2, 3 and 4, and includes a trim flap 5 pivotally connected to the hull 1 of the vessel by means of a flexible strap 3. Positioned between the trim flap 5 and the bottom of the vessel is a flexible, wedge-shaped actuator bag 7, the interior of which communicates via a line 9 with an opening 11 disposed in an angular plate 13 fixed to the stern of the vessel at the side of the trim flap 5, and forms an extension of the bottom of the boat.

Located behind the opening 11 is a regulator flap 15 which is mounted on the plate 13 and the dimensions of which are mainly dependent on the size of the opening 11 and which is pivotally connected with the plate 13 and can be swung down by means of a small actuator bag 17 mounted between the flap 15 and the plate 13. Pressure medium is passed to the bag 17 through a line 19 which in the embodiment of FIGS. 1 and 2 passes to an operating unit 21 in the cockpit of the vessel. FIG. 1 shows a similar line 23 to a corresponding trim flap (not shown) on the starboard side of the vessel.

The flap is extended or swung out when pressure medium is passed to bag 17 of the regulator flap '15, whereby the bypassing water creates a dynamic pressure rise in front of the flap at the opening 1 l. The pressure is transmitted through the line 9 to the actuator bag 7 of the trim flap 5, whereupon the bag is inflated and the trim flap moved through an angle which is thus dependent on the pressure part to the bag 17 of the regulator flap 15. The vessel shown in FIG. 1 is provided on the starboard side with a second trim flap operating arrangement which is illustrated more specifically in FIG. 5. The trim flap 25 in this embodiment is also connected with the bottom of the boat by means of a flexible strap 3, and an actuator bag 27 is mounted between the trim flap 25 on the bottom of the boat. In this embodiment, however, an opening 29 is disposed in the actual trim flap, and the actuator bag 27 is provided with an opening 31 situated opposite the opening 29. In the embodiment being described the regulator flap and its actuator bag 17 are mounted directly onto the trim flip behind the opening 29. As with the embodiment previously described the regulator flap 15 is small in size as compared with the actual trim flap 25, and hence the trim flap can be regulated by servo action with the assistance of a very small regulating force.

FIG. 6 shows the trim flap of FIGS. 2-4, In this instance, however, the operating pressure line 9 to the actuator bag 7 is connected to a cylindrical body 33 which is rotatably mounted with an essentially vertical axis in a holder 35 which is fixed to the stern of the vessel. The cylindrical body 33 is provided with an inner passage 37, at the one end of which the line 9 of the actuator bag 7 is connected and the other end of which opens out into an opening 39 in the cylindrical surface of said body. The cylindrical body 33 is so situated that the opening 39 is located in the water flow beneath the bottom of the boat at the side of the trim flap 5. When the opening 39 faces forwards it is subjected to the total dynamic pressure on the bypassing water. By turning the cylinder in either direction the pressure in the opening 39 decreases until finally a subpressure occurs. Thus, this arrangement provides for good regulation of the pressure in the actuator bag 7 of the trim flap 5.

FIG. 7 is a plan view and FIG. 8 a side view of an arrangement which lacks movable parts and is adapted to automatically regulate a trim flap. In this embodiment the pressure line 9 to the actuator bag 7 of the trim flap 5 is connected to a sensing body 41 which is arranged to project out from the side of the boat in the proximity of its stern portion. The sensing body 41 is provided with an inner passage 43, the operating pressure line 9 of the trim flap being connected to one end thereof, and the other end of which opens out into an opening 45 in the under surface 47 of the leading edge of the sensing body. The sensing body should be so shaped and located, and the opening so located in the sensing body that pronounced changes in the flow occur at the opening 45 when the angle of attack of the boat is changed. This function is obtained with the shown position of the sensing body at the side of the boat stern below the water line A-A. The sensing body may for example have wing profile, and the opening should then be located below the leading edge thereof where great changes in flow and pressure occur as results of changes in the angle of attack. When the boat is started it has a large angle of attack and pressure occurs at the opening 45. Water is also pressed out sideways from under the boat bottom at low speed and flows past the sensing body. Athigh speed this water flow is decreased, and the sensing body may also sense this change in water flow. The pressure at the opening 45 is transmitted to the actuator bag 7 which extends the trim flap 5. When the boat has achieved higher speed and a planing attitude, it has a smaller angle of attack. The overpressure at the opening 45 has now decreased substantially or disappeared totally. The trim flap 5 is now pushed up by the water flow.

In another embodiment of the invention the device can be placed at the rudder of the vessel. FIG. 9 illustrates in horizontal section the rear portion of a boat rudder which is provided on either side thereof with a flap 82 and 84, respectively, and an actuator bag 86 and 88, respectively. The bag 86 is shown in a collapsed condition while the bag 88 is shown inflated. The flaps and the bags are fixed to the rudder in a manner similar to the way the trim flaps are connected to the bottom of the boat. In the embodiment of FIG. 9 the bags are actuated with the assistance of a servodevice which includes pressure tubes 90 and 92, the interior of said tubes communicating with the interior of the bags 86 and 88, respectively, through openings 91 and 93, respectively. Positioned in the pressure tubes are valve flaps 94 and 96, respectively, which are actuated by means of a cable arrange ment or compressed air operating means 95,100 in a-suitable manner.

FIGS. 10 and 1 1 show two alternative ways of arranging the flaps or control surfaces at the rudder.

In the embodiment of FIG. 10 the control surfaces 102 extend along the whole of the vertical rear edge of the rudder 104. The actual rudder 104 is held immovable by means of fittings 106 and steering of the vessel is accomplished solely by inflating to the desired extent either of the actuator bags 86 or 88.

In the embodiment of FIG. 11 the flaps 110 extend along but a portion of the vertical rear edge of the rudder 112. In this instance the rudder is not locked in position but is free to move on its rudder post 114. bssel control is obtained by servo action. When either of the small flaps 110 is'extended or swung out, the water pressure will generate torque on the rudder 112 to cause said rudder to be swung in the opposite direction to the actuated flap. Thus the vessel is steered as by swinging its normal rudder.

The invention is not limited to the embodiments described above, but its scope is determined by the following claims. The pressure space has been formed by a flexible bag in the above embodiments since this arrangement offers a number of advantages. For some installations the pressure space may, however, comprise a volume limited by rigid walls, one wall being fixed to the boat or the member to be subjected to the control force, whereas another rigid wall is movable in dependence of the pressure in said space. One edge of one wall is slidable in sealing engagement along a seal portion such as a sealing flange connected to the other wall. The seal does not have to be complete since sufficient actuating force can be exerted in spite of a certain leakage.

The accompanying FIG. 12 shows a device as described above. At the rear lower edge of the boat hull l, a trim flap is pivoted at a hinge 122. A plate 124 extends at an angle with the flap 120 from the hinge 122 upwards along the boat transom 126. The upper edge of plate 124 is slidable in sealing engagement with a shield 128 extending from the transom 126. Also the side edges of the plate 124 may slide along the side walls 130 of the shield in a sealing manner. A conduit 132 extends from a hole 134 in the plate and an opening 136 in the trim flap 120. A regulator flap 138 is located behind the opening 136. This regulator flap 138 is of the construction described above and is actuated by a bag 140 which may be pressurized through a conduit 142 corresponding to the conduit 19 in FIGS. 1-5. When the regulator flap is extended, a pressure rise occurs at the opening 136 whereby water is forced into the pressure space formed between the transom and the plate 124. The plate 124 will then pivot out from its rest position adjacent the transom to a position depending on the pressure in the chamber. The seal does not have to be complete since a certain leakage between the plate 124 and the shield 128 and the walls thereof, and also at the hinge 122, may be tolerated.

What I claim is:

1. A boat comprising a hull with a stern and a bottom, a trim attachment mounted on the hull adjacent the juncture of the stern and the bottom, said attachment comprising a tab having a front edge and a rear edge and being secured to the hull at its front edge, said tab having a control surface that extends rearwardly in contact with the water, expansible chamber means disposed directly between the trim attachment and the hull and bearing against the trim attachment, means communicating with the water adjacent the hull to apply to the interior of said expansible chamber means the dynamic pressure head of said water that results from the movement of the boat through the water, the boat having a rudder, there being a pair of said control surfaces mounted one at each side of the rudder, and control means for selective actuation of the control surfaces to change the course of the vessel, the rudder being fixed and the control surfaces functioning as rudder surfaces.

2. A boat as claimed in claim 1, said expansible chamber means comprising a flexible bag.

3. A power boat comprising a hull with a stern and a bottom, a trim attachment carried by the hull adjacent the juncture of the stern and the bottom, said attachment comprising a tab having a front edge and a rear edge and being secured to the hull at its front edge, said tab having a control surface that extends downwardly rearwardly in contact with the water, expansible chamber means bearing against the trim attachment, and means having an opening communicating with the water adjacent the hull to apply to the interior of said expansible chamber means the dynamic pressure head of said water that results from the movement of the boat through the water thereby to alter the attitude of the boat in the water, said opening being disposed in a surface which projects from the side of the vessel at the stern thereof whereby the opening senses changes in the water flow which occur as a result of changes in the attitude of the boat.

4. A boat comprising a hull with a stern and a bottom, a trim attachment carried by the hull adjacent the juncture of the stern and the bottom, said attachment comprising a tab having a front edge and a rear edge and being secured to the hull at its front edge, said tab having a control surface that extends downwardly rearwardly in contact with the water, expansible chamber means bearing against the trim attachment over an area substantially the same as the area of said control surface, means having an opening communicating with the water adjacent the hull to apply to the interior of said expansible chamber means the dynamic pressure head of said water that results from the movement of the boat through the water, and means for changing the surface geometry in the immediate proximity of said opening thereby to vary the pressure in said expansible chamber means.

5. A boat as claimed in claim 4, and a regulator flap on the surface in which said opening is disposed behind said opening in the flow direction of the water, the area of said flap being small in relation to the area of said control surface, said flap being swingable away from its support surface to cause increased pressure at said opening.

6. A boat as claimed in claim 5, said opening being disposed in said control surface and said regulator flap being connected to said control surface behind the opening.

7. The arrangement of claim 6, characterized in that between the regulator flap and its support surface there is mounted a regulator flap actuator bag, the interior of which communicates with pressure setting means for setting the pressure of said bag and thus extending the regulator flap from its seating.

8. A power boat comprising a hull with a stern and a bottom, a trim attachment carried by the hull adjacent the juncture of the stern and the bottom, said attachment comprising a tab having a front edge and a rear edge and being secured to the hull at its front edge, said tab having a control surface that extends downwardly rearwardly in contact with the water, expansible chamber means bearing against the trim attachment, means having an opening communicating with the water adjacent the hull to apply to the interior of said expansible chamber means the dynamic pressure head of said water that results from the movement of the boat through the water, and means for varying the position of said opening relative to the flow direction of the water so as to vary the pressure prevailing in said chamber.

9. A boat as claimed in claim 8, said means for varying the position of said opening comprising a cylindrical body rotatable about its axis, said opening being disposed in the cylindrical surface of said body. 

1. A boat comprising a hull with a stern and a bottom, a trim attachment mounted on the hull adjacent the juncture of the stern and the bottom, said attachment comprising a tab having a front edge and a rear edge and being secured to the hull at its front edge, said tab having a control surface that extends rearwardly in contact with the water, expansible chamber means disposed directly between the trim attachment and the hull and bearing against the trim attachment, means communicating with the water adjacent the hull to apply to the interior of said expansible chamber means the dynamic pressure head of said water that results from the movement of the boat through the water, the boat having a rudder, there being a pair of said control surfaces mounted one at each side of the rudder, and control means for selective actuation of the control surfaces to change the course of the vessel, the rudder being fixed and the control surfaces functioning as rudder surfaces.
 2. A boat as claimed in claim 1, said expansible chamber means comprising a flexible bag.
 3. A power boat comprising a hull with a stern and a bottom, a trim attachment carried by the hull adjacent the juncture of the stern and the bottom, said attachment comprising a tab having a front edge and a rear edge and being secured to the hull at its front edge, said tab having a control surface that extends downwardly rearwardly in contact with the water, expansible chamber means bearing against the trim attachment, and means having an opening communicating with the water adjacent the hull to apply to the interior of said expansIble chamber means the dynamic pressure head of said water that results from the movement of the boat through the water thereby to alter the attitude of the boat in the water, said opening being disposed in a surface which projects from the side of the vessel at the stern thereof whereby the opening senses changes in the water flow which occur as a result of changes in the attitude of the boat.
 4. A boat comprising a hull with a stern and a bottom, a trim attachment carried by the hull adjacent the juncture of the stern and the bottom, said attachment comprising a tab having a front edge and a rear edge and being secured to the hull at its front edge, said tab having a control surface that extends downwardly rearwardly in contact with the water, expansible chamber means bearing against the trim attachment over an area substantially the same as the area of said control surface, means having an opening communicating with the water adjacent the hull to apply to the interior of said expansible chamber means the dynamic pressure head of said water that results from the movement of the boat through the water, and means for changing the surface geometry in the immediate proximity of said opening thereby to vary the pressure in said expansible chamber means.
 5. A boat as claimed in claim 4, and a regulator flap on the surface in which said opening is disposed behind said opening in the flow direction of the water, the area of said flap being small in relation to the area of said control surface, said flap being swingable away from its support surface to cause increased pressure at said opening.
 6. A boat as claimed in claim 5, said opening being disposed in said control surface and said regulator flap being connected to said control surface behind the opening.
 7. The arrangement of claim 6, characterized in that between the regulator flap and its support surface there is mounted a regulator flap actuator bag, the interior of which communicates with pressure setting means for setting the pressure of said bag and thus extending the regulator flap from its seating.
 8. A power boat comprising a hull with a stern and a bottom, a trim attachment carried by the hull adjacent the juncture of the stern and the bottom, said attachment comprising a tab having a front edge and a rear edge and being secured to the hull at its front edge, said tab having a control surface that extends downwardly rearwardly in contact with the water, expansible chamber means bearing against the trim attachment, means having an opening communicating with the water adjacent the hull to apply to the interior of said expansible chamber means the dynamic pressure head of said water that results from the movement of the boat through the water, and means for varying the position of said opening relative to the flow direction of the water so as to vary the pressure prevailing in said chamber.
 9. A boat as claimed in claim 8, said means for varying the position of said opening comprising a cylindrical body rotatable about its axis, said opening being disposed in the cylindrical surface of said body. 